Field of the Invention
The present invention relates to a vertical spigot joint. The joint seals the space between a generally upwardly directed socket and a pipe filling in the socket.
Such a joint is used, for example, to seal the connection of a metal riser pipe to a socket in a metal gas collecting main in a coke-oven battery. Gases derived from coking coals are discharged from the main through such riser pipes, usually being cooled by a water scrubber close to the spigot joint. The gases contain hydrocarbons, chlorine compounds and sulphur and it is the purpose of the spigot joint to prevent gas leaking from the joint, as this could give rise to unacceptable working conditions and to considerable environmental pollution.
However the riser pipes and the gas mains are connected to different structures and the forces caused by the passage of a medium of variable pressure and temperature, and the thermal expansion and contraction of the pipe and socket causes relative movement of the pipe and socket. In the case of the riser pipe of a coke-oven battery this movement may be of the order of 10 mm in both the horizontal and vertical directions. The joint must be able to prevent gas leakage from the joint despite the movement of the pipe and socket.
Attempts have been made to find a reliable joint for sealing the pipe to the socket but none of these has been completely successful.